Revealing Lithium Nitrate-Mediated Solid-Electrolyte Interphase of Lithium Metal Anode via Cryogenic Transmission Electron Microscopy.

The cycle stability of lithium metal anode (LMA) largely depends on solid-electrolyte interphase (SEI). Electrolyte engineering is a common strategy to adjust SEI properties, yet understanding its impact is challenging due to limited knowledge on ultrafine SEI structures. Herein, using cryogenic transmission electron microscopy, we reveal the atomic-level SEI structure of LMA in ether-based electrolytes, focusing on the role of LiNO3 additives in SEI modulation at different temperature (25 and 50 °C). Poor cycle stability of LMA in the baseline electrolyte without LiNO3 additives stems from the Li2CO3-rich mosaic-type SEI. Increased LiNO3 content and elevated operating temperature enhance cyclic performance by forming bilayer or multilayer SEI structures via preferential LiNO3 decomposition, but may thicken the SEI, leading to reduced initial Coulombic efficiency and increased overpotential. The optimal SEI features a multilayer structure with Li2O-rich inner layer and closely packed grains in the outer layer, minimizing electrolyte decomposition or corrosion.

Sub-3 nm Pt@Ru toward Outstanding Hydrogen Oxidation Reaction Performance in Alkaline Media.

Anion-exchange membrane fuel cells (AEMFCs) are promising alternative hydrogen conversion devices. However, the sluggish kinetics of the hydrogen oxidation reaction in alkaline media hinders further development of AEMFCs. As a synthesis method commonly used to prepare disordered PtRu alloys, the impregnation process is ingeniously designed herein to synthesize sub-3 nm Pt@Ru core-shell nanoparticles by sequentially reducing Pt and Ru at different annealing temperatures. This method avoids complex procedures and synthesis conditions for organic synthesis systems, and the atomic structure evolution of the synthesized core-shell nanoparticles can be tracked. The synthesized Pt@Ru electrocatalyst shows an ultrasmall average size of ∼2.5 nm and thereby a large electrochemical surface area (ECSA) of 166.66 m2 gPt+Ru-1. Exchange current densities (j0) normalized to the mass (Pt + Ru) and ECSA of this electrocatalyst are 8.0 and 5.8 times as high as those of commercial Pt/C, respectively. To the best of our knowledge, the achieved mass-normalized j0 measured by rotating disk electrodes is the highest reported so far. The membrane electrode assembly test of the Pt@Ru electrocatalyst shows a peak power density of 1.78 W cm-2 (0.152 mgPt+Ru cmanode-2), which is higher than that of commercial PtRu/C (1.62 W cm-2, 0.211 mgPt+Ru cmanode-2). The improvement of the intrinsic activity can be attributed to the electron transfer from the Ru shell to the Pt core, and the ultrafine particles further enhance the mass activity. This work reveals the feasibility of using simple impregnation to synthesize fine core-shell nanocatalysts and the importance of investigating the atomic structure of PtRu nanoparticles and other disordered alloys.

Head-to-head comparison of prostate-specific membrane antigen PET and multiparametric MRI in the diagnosis of pretreatment patients with prostate cancer: a meta-analysis.

OBJECTIVES: To compare prostate-specific membrane antigen (PSMA) PET with multiparametric MRI (mpMRI) in the diagnosis of pretreatment prostate cancer (PCa). METHODS: Pubmed, Embase, Medline, Web of Science, and Cochrane Library were searched for eligible studies published before June 22, 2022. We assessed risk of bias and applicability by using QUADAS-2 tool. Data synthesis was performed with Stata 17.0 software, using the "midas" and "meqrlogit" packages. RESULTS: We included 29 articles focusing on primary cancer detection, 18 articles about primary staging, and two articles containing them both. For PSMA PET versus mpMRI in primary PCa detection, sensitivities and specificities in the per-patient analysis were 0.90 and 0.84 (p<0.0001), and 0.66 and 0.60 (p <0.0001), and in the per-lesion analysis they were 0.79 and 0.78 (p <0.0001), and 0.84 and 0.82 (p <0.0001). For the per-patient analysis of PSMA PET versus mpMRI in primary staging, sensitivities and specificities in extracapsular extension detection were 0.59 and 0.66 (p =0.005), and 0.79 and 0.76 (p =0.0074), and in seminal vesicle infiltration (SVI) detection they were 0.51 and 0.60 (p =0.0008), and 0.93 and 0.96 (p =0.0092). For PSMA PET versus mpMRI in lymph node metastasis (LNM) detection, sensitivities and specificities in the per-patient analysis were 0.68 and 0.46 (p <0.0001), and 0.91 and 0.90 (p =0.81), and in the per-lesion analysis they were 0.67 and 0.36 (p <0.0001), and 0.99 and 0.99 (p =0.18). CONCLUSION: PSMA PET has higher diagnostic value than mpMRI in the detection of primary PCa. Regarding the primary staging, mpMRI has potential advantages in SVI detection, while PSMA PET has relative advantages in LNM detection. CLINICAL RELEVANCE STATEMENT: The integration of prostate-specific membrane antigen (PSMA) PET into the diagnostic pathway may be helpful for improving the accuracy of prostate cancer detection. However, further studies are needed to address the cost implications and evaluate its utility in specific patient populations or clinical scenarios. Moreover, we recommend the combination of PSMA PET and mpMRI for cancer staging. KEY POINTS: • Prostate-specific membrane antigen PET has higher sensitivity and specificity for primary tumor detection in prostate cancer compared to multiparametric MRI. • Prostate-specific membrane antigen PET also has significantly better sensitivity and specificity for lymph node metastases of prostate cancer compared to multiparametric MRI. • Multiparametric MRI has better accuracy for extracapsular extension and seminal vesicle infiltration compared to ate-specific membrane antigen PET.

Ubiquitination of ASCL1 mediates CD47 transcriptional activation of the AKT signaling pathway, and glycolysis promotes osteogenic differentiation of hBMSCs.

Bones are extremely dynamic organs that continually develop and remodel. This process involves changes in numerous gene expressions. hBMSC cells can promote osteogenic differentiation. The purpose of this study was to elucidate the mechanism by which ASCL1 promotes osteogenic differentiation in hBMSC cells while decreasing glycolysis. hBMSCs were induced to differentiate into osteoblasts. The ASCL1 expression level during hBMSC osteogenic differentiation was measured by RT‒qPCR, Western blotting, and immunofluorescence. The differentiation level of osteoblasts was observed after staining with ALP and alizarin red. ChIP-qPCR were used to determine the relationship between ASCL1 and CD47, and the expression of glycolysis-related proteins was detected. Overexpression of ASCL1 was used to determine its impact on osteogenic differentiation. si-USP8 was used to verify the ubiquitination of ASCL1-mediated CD47/AKT pathway's impact on hBMSC glycolysis and osteogenic differentiation. The results showed that the expression of ASCL1 was upregulated after the induction of osteogenic differentiation in hBMSCs. From a functional perspective, knocking down USP8 can promote the ubiquitination of ASCL1, while the osteogenic differentiation ability of hBMSCs was improved after the overexpression of ASCL1, indicating that ASCL1 can promote the osteogenic differentiation of hBMSCs. In addition, USP8 regulates the ubiquitination level of ASCL1 and mediates CD47 transcriptional regulation of the AKT pathway to increase the glycolysis level of hBMSCs and cell osteogenic differentiation. USP8 ubiquitination regulates the level of ASCL1. In addition, ubiquitination of ASCL1 mediates CD47 transcription to activate the AKT signaling pathway and increase hBMSC glycolysis to promote osteogenic differentiation.

Differing Electrolyte Implication on Anion and Cation Intercalation into Graphite.

Emerging dual-graphite batteries (DGBs) capture extensive interest for their high output voltage and exceptional cost-effectiveness. Yet, developing electrolytes compatible with both the cathode and anode stands to be a tremendous challenge, and how electrolyte impacts anion and cation intercalation into graphite remains inexplicit or controversial. Herein, we have evaluated the performance of graphite anode and cathode in typical ethyl methyl carbonate (EMC) based electrolytes and unveiled their electrode-electrolyte interphase using Cryogenic transmission electron microscopy (Cryo-TEM). The addition of fluoroethylene carbonate (FEC) brings substantial improvement in cycle stability and Coulombic efficiency for both the graphite cathode and anode, but its implication on cation and anion intercalation differs. FEC is involved in anodic side reactions to produce a LiF-embedded solid-electrolyte interphase layer. It is much thinner and more uniform than that formed in the electrolyte without FEC, which is correlated with less graphite exfoliation and enhanced stability. As for the graphite cathode, both basal and edge planes are largely bare, and only few scattered byproducts are found. In addition, we also reveal layer bending and local lattice disordering of the graphite cathode based on multiple Cryo-TEM images, which are speculated to be caused by high lattice strain induced by anion intercalation and local oxidation under high voltage. The absence of cathode-electrolyte interphase (CEI) layers overturns the paradigm of attributing cathodic performance to CEI features and is regarded as a fundamental reason for severe self-discharge of graphite cathode. FEC helps to alleviate graphite exfoliation issues and enhance cycle stability, and we ascribe it to weakened solvation, which means reduced probability of solvent co-intercalation during charging, rather than compositional changes of cathodic byproducts.

Borate-Based Artificial Solid-Electrolyte Interphase Enabling Stable Lithium Metal Anodes.

Lithium (Li) metal is considered as the "holy grail" of anode materials for next-generation high energy batteries. However, notorious dendrite growth and interfacial instability could induce irreversible capacity loss and safety issues, limiting the practical application of Li metal anodes. Herein, we develop a novel approach to construct a borate-based artificial solid-electrolyte interphase (designated as B-SEI) through the reaction of metallic Li with triethylamine borane (TEAB). According to our cryogenic electron microscopy (Cryo-EM) characterization results, the artificial SEI adopts a glass-crystal bilayer structure, which facilitates uniform Li-ion transport and inhibits dendrite growth during Li plating. Benefiting from such an artificial SEI, the Li anode delivers an improved rate performance and prolonged cycle life. The symmetric Li/B-SEI||Li/B-SEI cell can maintain stable cycling for 700 h at a high current density of 3 mA cm-2. The full-cell pairing Li/B-SEI with LiFePO4 only exhibits minimal capacity decay after 500 cycles in a conventional carbonate-based electrolyte. This work demonstrates the feasibility of building a boride-based artificial SEI to stabilize the Li metal anode based on microscopic characterization results and comprehensive electrochemical data, which represents a promising avenue to develop practical Li metal batteries.

Catalytic Chemistry Derived Artificial Solid Electrolyte Interphase for Stable Lithium Metal Anodes Working at 20†mA cm-2 and 20†mAh cm-2.

A stable solid electrolyte interphase (SEI) layer is crucial for lithium metal anode (LMA) to survive in long-term cycling. However, chaotic structures and chemical inhomogeneity of natural SEI make LMA suffering from exasperating dendrite growth and severe electrode pulverization, which hinder the practical application of LMAs. Here, we design a catalyst-derived artificial SEI layer with an ordered polyamide-lithium hydroxide (PA-LiOH) bi-phase structure to modulate ion transport and enable dendrite-free Li deposition. The PA-LiOH layer can substantially suppress the volume changes of LMA during Li plating/stripping cycles, as well as alleviate the parasitic reactions between LMA and electrolyte. The optimized LMAs demonstrate excellent stability in Li plating/stripping cycles for over 1000 hours at an ultra-high current density of 20 mA cm-2 in Li||Li symmetric cells. A high coulombic efficiency up to 99.2 % in Li half cells in additive-free electrolytes is achieved even after 500 cycles at a current density of 1 mA cm-2 with a capacity of 1 mAh cm-2 .

Development and Validation of the Missed Nursing Care Tool for Pre-Operative Patients with Lung Cancer in China.

Introduction: Current research suggests that missed nursing care is widespread in preoperative lung cancer patients in China, and preoperative airway management nursing care for lung cancer patients is not standardized. Missed nursing care for preoperative lung cancer patients, on the other hand, is rarely investigated, particularly from the patient's perspective. This study aimed to develop and validate the MISSCARE Survey for pre-operative patients with lung cancer in China. Methods: This study generated the preliminary draft of the MISSCARE Survey - Lung Cancer Patient (MS-LCP) and tested its reliability and stability through three rounds of lung cancer resection (494, 50, and 309 cases, respectively). 20 patients and 6 experts determined the face and content validity. EFA and CFA assessed construct and convergent validity. Internal consistency, including Cronbach's alpha, Spearman-Brown reliability, and re-test reliability, was also examined. Results: The scale contained 15 items, including specific care, communicative care, timely care, and basic care. KMO was 0.932 (> 0.6), and Bartlett's Test of Sphericity showed P = 0.000 (<0.05). The attribution factor's item loads ranged from 0.765 to 0.853, accounting for 82.20% of the variation. The scale's Cronbach's alpha, Spearman-Brown, and retest reliability were 0.945, 0.879, and 0.824. CFA showed goodness of fit (RMSEA = 0.021, χ2/df = 1.138, GFI = 0.900, AGFI = 0.945, CFI = 0.996, NFI = 0.967, IFI = 0.996). For each dimension, AVE ranged from 0.555 to 0.717 (>0.50) and CR from 0.861 to 0.904 (>0.70). Conclusion: The MS-LCP was reliable and valid in this study, making it appropriate for the Chinese lung cancer patient population. This tool is more objective in its presentation of missed nursing care, assisting nursing staff in optimizing nursing procedures before surgery, increasing the implementation of higher-quality tumor care, and promoting the recovery of lung cancer surgery patients.

Revealing Structural Insights of Solid Electrolyte Interphase in High-Concentrated Non-Flammable Electrolyte for Li Metal Batteries by Cryo-TEM.

High-concentrated non-flammable electrolytes (HCNFE) in lithium metal batteries prevent thermal runaway accidents, but the microstructure of their solid electrolyte interphase (SEI) remains largely unexplored, due to the lack of direct imaging tools. Herein, cryo-HRTEM is applied to directly visualize the native state of SEI at the atomic scale. In HCNFE, SEI has a uniform laminated crystalline-amorphous structure that can prevent further reaction between the electrolyte and lithium. The inorganic SEI component, Li2 S2 O7 , is precisely identified by cryo-HRTEM. Density functional theory (DFT) calculations demonstrate that the final Li2 S2 O7 phase has suitable natural transmission channels for Li-ion diffusion and excellent ionic conductivity of 1.2 × 10-5 S cm-1 .

Na-K Alloy Anode for High-Performance Solid-State Sodium Metal Batteries.

Rechargeable solid-state Na metal batteries (SSNMB) can offer high operational safety and energy density. However, poor solid-solid contact between the electrodes and the electrolyte can dramatically increase interfacial resistance and Na dendrite formation, even at low current rates. Therefore, we developed a carbon-fiber-supported liquid Na-K alloy anode that ensures close anode-electrolyte contact, enabling superior cycle stability and rate capability. We then demonstrated the first cryogenic transmission electron microscopy (cryo-TEM) characterization of an SSNMB, capturing the evolution of solid-electrolyte interphase (SEI) and revealing both crystalline and amorphous phases, which could facilitate ion transport and prevent continuous side reactions. By enhancing contact between the Na-K alloy and solid-state electrolyte, these symmetric cells are capable of cycling for over 800 h without notable increased polarization and enable an unprecedented critical current density (CCD) at 40 mA cm-2. Our liquid Na-K alloy approach offers a promising strategic avenue toward commercial SSNMBs.

Polyphyllin I improves myocardial damage in coronary artery disease via modulating lipid metabolism and myocardial apoptosis.

Polyphyllin I (PPI) is a famous traditional medicine ingredient, which has been explored in wide range of areas. Nevertheless, whether PPI exerts any functions in coronary artery disease (CAD) is still uncertified. Herein, we probed the effect and mechanism of PPI on lipid metabolism and myocardial dysfunction in myocardial cells and CAD rat model. Hypoxia/reoxygenation (H/R)-treated H9c2 cells model was constructed for the in vitro experiments, and CAD model in vivo was established by high-fat feeding. After management with PPI, the correlated factors of lipid metabolism and myocardial function were investigated. The apoptosis of myocardial cells was assessed by Annexin V-FITC/PI kit and TUNEL staining. The apoptosis-associated factors (caspase 3, cleaved caspase 3, Bax, and Bcl-2) were tested by Western blot analysis. The MEK/ERK inhibitor was applied and the functions of MEK/ERK pathway in myocardial damage were investigated. H/R-treated H9c2 cells model was constructed for the in vitro experiments, and CAD model in vivo was established by high-fat feeding. After management with PPI, the correlated factors of lipid metabolism and myocardial function were investigated. The apoptosis of myocardial cells was assessed by Annexin V-FITC/PI kit and TUNEL staining. The apoptosis-associated factors (caspase 3, cleaved caspase 3, Bax, and Bcl-2) were tested by Western blot analysis. The MEK/ERK inhibitor was applied and the functions of MEK/ERK pathway in myocardial damage were investigated. PPI improved lipid metabolism disorder in H/R-induced H9c2 cells or in CAD rat model. Additionally, PPI attenuated myocardial dysfunction in CAD rats via enhancing left ventricular systolic pressure, maximum rate of change of left ventricular pressure (±dp/dtmax ), and arterial blood flow (CF). The apoptosis of myocardial cells was lessened by PPI management, which was further verified by reducing Bax and cleaved caspase 3 expression. Furthermore, PD0325901 (MEK/ERK inhibitor) weakened the effect of PPI on myocardial dysfunction, lipid metabolism, and myocardial cell apoptosis in CAD rats. The research confirmed the protective effect of PPI on myocardial damage in CAD, which was regulated by MEK/ERK pathway.

Bismuth Ferrite as an Electrocatalyst for the Electrochemical Nitrate Reduction.

Electrochemical nitrate reduction has become an appealing "waste-to-wealth" approach for sustainable NH3 synthesis owing to its mild operating conditions. However, developing catalysts with high activities and Faradaic efficiencies for this complicated eight-electron reaction is a great challenge. Herein, bismuth ferrite (BiFeO3) flakes, with a distorted perovskite-type structure, are demonstrated to be excellent catalysts for electrochemical NH3 synthesis via nitrate reduction, with a maximum Faradaic efficiency of 96.85%, NH3 yield of 90.45 mg h-1 mgcat-1, at -0.6 V vs. reversible hydrogen electrode. During the nitrate reduction reaction, the crystalline BiFeO3 rapidly converts into an amorphous phase, which is stable in the long term reaction. These results open a new window for rational design of more active and durable electrocatalysts.

Evaluation methods of a rat sciatic nerve crush injury model.

BACKGROUND: The rat sciatic nerve crush injury model is one of the most commonly used models to research peripheral nerve injury (PNI), however, the evaluation of the model preparation lacks exact standards. This study aimed to investigate accurately assessment methods for research concerning the rat sciatic nerve crush injury. METHODS: The sciatic nerve crush injury model of was performed using the FST toothless forceps. The corresponding locations and pressures of different ratchet strengths were assessed by using CMAP, behavioral, and morphological methods. RESULTS: In each group of PNI, motor and sensory functions were gradually restricted on the injured side of rats as the applied pressure increased. CMAP was more sensitive to nerve injury arising out of the force values obtained from the forceps. CONCLUSIONS: As a sensitive indicator for PNI, the neuroelectrophysiological examination was more likely to reflect the morphological changes of injured nerves. These findings may provide a standardized approach to sciatic crush injury modelling.

Enabling Ultrastable Alkali Metal Anodes by Artificial Solid Electrolyte Interphase Fluorination.

The high specific capacity of alkalic metal (Li, Na, and K) anodes has drawn widespread interest; however, the practical applications of alkalic metal anodes have been hampered by dendrite growth and interfacial instability, resulting in performance deterioration and even safety issues. Here, we describe a simple method for building tunable fluoride-based artificial solid-electrolyte interphase (SEI) from the fluorination reaction of alkali metals with a mild organic fluorinating reagent. Comprehensive characterization by advanced electron microscopes shows that the LiF-based artificial SEI adopts a crystal-glass structure, which enables efficient Li ion transport and improves structural integrity against the volume changes that occur during Li plating/stripping. Compared with bare Li anode, the ones with artificial SEI exhibit decreased voltage hysteresis, enhanced rate capability, and prolonged cycle life. This method is also applied to generate fluoride-based artificial SEI on Na and K metal anodes that brings significant improvement in battery performance.

Data mining-based detection of the clinical effect on motion style acupuncture therapy combined with conventional acupuncture therapy in chronic neck pain.

BACKGROUND: Neck pain is the most common symptom of cervical spondylosis. OBJECTIVE: To discuss the indications for conventional acupuncture therapy (CAT) and motion style acupuncture therapy (MSAT) combined with CAT in neck pain patients using data mining. METHOD: Seventy-six participants with neck pain were recruited and randomly divided into two paralleled groups. Participants in intervention group received two-course MSAT at Houxi (SI3) and CAT at local neck region, while the control group received CAT at neck only. Take the SF-36 score scale and pain pressure threshold (PPT) values as the raw data and use data-mining to evaluate the clinical effect of two treatments. RESULT: Both groups have the best effect after one-time and one-course treatment. The main factors influencing effect most are Role-Emotional (RE), Physical Functioning (PF) and Social Functioning (SF) in intervention group, while it transfers to General Health (GH), RE and SF in control group. To patients in intervention group who scores 41.70 to 68.70 in PF before treatment, MSAT can effectively improve the restriction of activities and play an analgesic effect; to patients in control group who score 56.09 to 66.09 in GH before treatment, CAT may have curative effect. CONCLUSION: Both MSAT and CAT can improve the life-quality of neck pain patients. Patients with high general health status before treatment can choose CAT, while patients who score mild to moderate decline in physiological function can choose MSAT combined with CAT.

Revealing the Intrinsic Atomic Structure and Chemistry of Amorphous LiO2-Containing Products in Li-O2 Batteries Using Cryogenic Electron Microscopy.

Aprotic lithium-oxygen batteries (LOBs) are promising energy storage systems characterized by ultrahigh theoretical energy density. Extensive research has been devoted to this battery technology, yet the detailed operational mechanisms involved, particularly unambiguous identification of various discharge products and their specific distributions, are still unknown or are subjects of controversy. This is partly because of the intrinsic complexity of the battery chemistry but also because of the lack of atomic-level insight into the oxygen electrodes acquired via reliable techniques. In the current study, it is demonstrated that electron beam irradiation could induce crystallization of amorphous discharge products. Cryogenic conditions and a low beam dosage have to be used for reliable transmission electron microscopy (TEM) characterization. High-resolution cryo-TEM and electron energy loss spectroscopy (EELS) analysis of toroidal discharge particles unambiguously identified the discharge products as a dominating amorphous LiO2 phase with only a small amount of nanocrystalline Li2O2 islands dispersed in it. In addition, uniform mixing of carbon-containing byproducts is identified in the discharge particles with cryo-EELS, which leads to a slightly higher charging potential. The discharge products can be reversibly cycled, with no visible residue after full recharge. We believe that the amorphous superoxide dominating discharge particles can lead researchers to reconsider the chemistry of LOBs and pay special attention to exclude beam-induced artifacts in traditional TEM characterizations.

Nerve growth factor promotes osteogenic differentiation of MC3T3-E1 cells via BMP-2/Smads pathway.

BACKGROUND: Exogenous nerve growth factor (NGF) can induce osteogenic precursor cell differentiation and promote fracture healing. However, the molecular mechanism by which NGF induces osteogenesis is not well understood. BMP-2 has good osteogenic efficacy and is one of the most osteogenic-inducing growth factors known. Therefore, this study aimed to determine whether NGF induces osteogenic differentiation of mouse embryonic osteogenic precursor cell line MC3T3-E1 by BMP-2 and search further mechanisms of NGF on BMP-2. METHODS: MC3T3-E1 cells were treated with NGF at a concentration gradient for indicated times, after which the cell viability was measured by CCK-8 kit. Osteogenic differentiation was detected with quantification of alkaline phosphatase (ALP) activity also visualized with ALP staining. The transcription and expression of relevant genes were detected by qPCR and western blotting, respectively. NGF's effect on BMP2 was studied with qPCR and luciferase reporter assay. The phosphorylation of Smads was probed with specific antibodies by western blotting, and the location of Smads was observed through immunofluorescence. RESULTS: We found that NGF promoted proliferation and osteogenic differentiation of MC3T3-E1, increased the expression level of BMP-2, as well as the phosphorylation and nuclear translocation of Smad1/5/8. However, neutralization of BMP-2 with si-BMP-2 or BMP-2 signal inhibitors reversed NGF induced phosphorylation and nuclear translocation of Smad1/5/8, as well as the expression of Runx2, type I collagen, osteocalcin and osteopontin. In addition, si-BMP-2 abrogated NGF-induced ALP activity. CONCLUSION: NGF induced osteogenic differentiation of MC3T3-E1 cells through BMP-2/Smads pathway and induction of Runx2. Our study would provide a theoretical basis for clinical treatment of fractures using NGF.

Twist-to-Untwist Evolution and Cation Polarization Behavior of Hybrid Halide Perovskite Nanoplatelets Revealed by Cryogenic Transmission Electron Microscopy.

Hybrid methylammonium lead iodide (MAPbI3) perovskite nanoplatelets (NPLs) have emerged as promising optoelectronic materials because of their remarkable properties in defect tolerance, band gap tunability, and light emission. However, the detailed formation mechanism, in particular the atomic structure information in the initial nucleation stage, stands as a mystery because of the intrinsic vulnerability toward moisture, electron beams, etc. By virtue of the imaging technique under the extremely low electron dose of the cryogenic TEM, atomic structures of MAPbI3 NPLs are imaged, and a twist-to-untwist structural evolution is captured. According to theoretical calculation results, the twist-to-untwist evolution is a spontaneous process, and the band gap will be reduced, which is further verified by the red shift of photoluminescence peaks with aging time. Moreover, MA cation polarization is observed by quantitative analysis of the atomic-resolution image of single-crystalline MAPbI3 NPLs, which demonstrates the high ion mobility in the lattice of the hybrid halide perovskites.

Three-dimensional visualization of lithium metal anode via low-dose cryogenic electron microscopy tomography.

The structure of lithium (Li) metal anode, including the Li metal and the solid electrolyte interphase (SEI), is critical to the investigation of cycle stability or decay mechanisms. The three-dimensional (3D) visualization of Li metal and SEI, however, has not been demonstrated yet, owing to the lack of 3D characterization techniques and the susceptibility of Li metal anode toward oxygen, moisture, as well as electron beam. Herein, we introduce a successful 3D presentation of deposited Li metal and SEI established via low-dose cryogenic electron microscopy tomography. The Li metal anode is imaged in low-dose mode at different tilt angles and then aligned and reconstructed into a 3D image through an expectation-maximization algorithm. The spherical Li deposits and SEI are confirmed in the 3D tomography of Li metal anode. It is also discovered that the Li metal corrodes and SEI turns concave owing to possible self-discharge after long-time rest.

Clarifying the Roles of Cobalt and Nickel in the Structural Evolution of Layered Cathodes for Sodium-Ion Batteries.

Layered sodium manganese-based oxides are appealing cathode candidates due to their high capacity and cost-effectiveness, yet performance degradation related with unwanted structural evolution still remains a disturbing disadvantage. Herein, atomic resolution STEM (scanning transmission electron microscopy) images of Na-extracted Na2/3NixCo1/3-xMn2/3O2 (x = 0, 1/6, 1/3) are collected and analyzed, to decipher the effect of cobalt and nickel substitution on the structural integrity of layered manganese-based oxides. Cobalt substitution is demonstrated to alleviate the lattice stress and retain the layered structure after sodium removal, and only a local P2-to-O2 phase transition could be identified. By contrast, various types of defects and phase transformation, including rarely reported P2-to-O3, are discovered in the Ni-substituted oxides. The generation of spinel and rock-salt phases is the critical evidence of cation mixing that leads to unrecoverable capacity loss. The interplay of different transition metals is complex, and compositional optimization is encouraged to minimize the effect of the concomitant phase transition.